There is today an increasing demand on transportation services. Delays are in general not accepted and the requirements on safety are high. Vehicles for transporting passengers or cargo, in particular trains, travel over large distances and in many cases in remote areas. This has several impacts on both safety and on-time arrival demands. For example, maintenance of the rail tracks and surrounding structures is increasingly important since e.g. a fallen post has an impact on safety and may also cause substantial delays.
Further, since in particular trains often travel in remote areas, they visit location which otherwise may not be easily accessible to people. Thus, in case of a malfunction of the train due to structural damages on the rail tracks, or on structures in the vicinity of the rail tracks, it may take some time for personnel to reach the place of the structural damage in order to repair the structures or the rails. It would therefore be desirable to monitor the structures and the rails to prevent such situations.
A prior art approach is to allow maintenance trains to travel the tracks in order to monitor in particular the rail tracks. Such a maintenance train travels the track a few times a year at most due to availability and cost. Furthermore, the prior art solutions discover damages that have already occurred, and these damages will often anyway compromise safety and cause delays, despite the possibility of detecting them.
Thus, a drawback of prior art solutions is that they are incapable of reliably identifying problems in at an early stage because they are unable to accurately identifying changes to structures near the rails, or changes to the rail itself.
Another drawback is that structural changes occurring over long time scales may not efficiently be taken into account.
There is therefore a need for a method for identifying already present or potential damages of this type in a simpler and more cost-effective way, thereby making it possible to use this more frequently, and there is also a need for a method being capable of identifying damages at an earlier stage.